[3/3] drm/i915/guc: drop cached copy of 'wq_head'

Commit Message

Dave Gordon April 14, 2016, 5:19 p.m. UTC

From: Alex Dai <[e-mail]>

Now that we keep the GuC client structure (and therefore the process
descriptor embedded therein) permanently mapped, we don't really need to
keep a local copy of the GuC's work-queue-head. So we can simplify the
code a little by not doing this.

Signed-off-by: Alex Dai <[e-mail]>
Signed-off-by: Dave Gordon <[e-mail]>
---
 drivers/gpu/drm/i915/i915_guc_submission.c | 16 ++++------------
 drivers/gpu/drm/i915/intel_guc.h           |  2 +-
 2 files changed, 5 insertions(+), 13 deletions(-)

Patch

diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index fbd57ca..fc27599 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -238,9 +238,6 @@  static int guc_ring_doorbell(struct i915_guc_client *gc)
 			db_exc.cookie = 1;
 	}
 
-	/* Finally, update the cached copy of the GuC's WQ head */
-	gc->wq_head = desc->head;
-
 	return ret;
 }
 
@@ -465,17 +462,10 @@  int i915_guc_wq_check_space(struct i915_guc_client *gc)
 	if (!gc)
 		return 0;
 
-	/* Quickly return if wq space is available since last time we cache the
-	 * head position. */
-	if (CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size) >= size)
-		return 0;
-
 	desc = gc->client_base + gc->proc_desc_offset;
 
 	while (timeout_counter-- > 0) {
-		gc->wq_head = desc->head;
-
-		if (CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size) >= size) {
+		if (CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size) >= size) {
 			ret = 0;
 			break;
 		}
@@ -490,10 +480,12 @@  int i915_guc_wq_check_space(struct i915_guc_client *gc)
 static int guc_add_workqueue_item(struct i915_guc_client *gc,
 				  struct drm_i915_gem_request *rq)
 {
+	struct guc_process_desc *desc;
 	struct guc_wq_item *wqi;
 	u32 tail, wq_len, wq_off, space;
 
-	space = CIRC_SPACE(gc->wq_tail, gc->wq_head, gc->wq_size);
+	desc = gc->client_base + gc->proc_desc_offset;
+	space = CIRC_SPACE(gc->wq_tail, desc->head, gc->wq_size);
 	if (WARN_ON(space < sizeof(struct guc_wq_item)))
 		return -ENOSPC; /* shouldn't happen */
 
diff --git a/drivers/gpu/drm/i915/intel_guc.h b/drivers/gpu/drm/i915/intel_guc.h
index 9ab3564..558793b 100644
--- a/drivers/gpu/drm/i915/intel_guc.h
+++ b/drivers/gpu/drm/i915/intel_guc.h
@@ -46,7 +46,7 @@  struct i915_guc_client {
 	uint32_t wq_offset;
 	uint32_t wq_size;
 	uint32_t wq_tail;
-	uint32_t wq_head;
+	uint32_t unused;		/* Was 'wq_head'		*/
 
 	/* GuC submission statistics & status */
 	uint64_t submissions[GUC_MAX_ENGINES_NUM];